Composition including silane-grafted polyolefin

ABSTRACT

A silane-grafted polyolefin composition is disclosed, and includes a desired reduced specific weight material. The composition finds application in a wide array of uses, and in particular automotive and uses such as weatherstrips, where this composition is used in place of conventional materials such as TPV and EPDM rubber formulations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This utility application claims the priority benefit of U.S. provisionalapplication Ser. No. 61/835,157, filed Jun. 14, 2013, the disclosure ofwhich is expressly incorporated by reference herein in its entirety.

BACKGROUND

The present disclosure relates to compositions such as weatherstripcompositions, weatherstrips that may be used in vehicles, and methodsfor forming the compositions and/or weatherstrips.

It is common in the motor vehicle industry to fashion decorativeabrasion resistant sections for various parts of an automobile byextruding such sections from certain polymeric materials. Examples oftypical abrasion resistant sections manufactured by such a processinclude weatherstrips. These weatherstrips are mounted on an automobiledoor surface and along the perimeter of automobile doors to provide aseal between the door and the automobile body as well as to protect boththe door and exterior objects when they come in contact with each other.The weatherstrips may prevent wind noise, water leaks, and dust fromentering the automobile.

Automotive glass run weatherstrip formulations typically utilize eitherthermoplastic vulcanizates (TPV) or ethylene propylene diene monomer(EPDM) rubber to achieve desired performance. TPVs are relatively easyto process but performance can be limited and material costs tend to behigh. EPDM rubber formulations can require many ingredients (e.g.,carbon black, petroleum-based oil, zinc oxide, miscellaneous fillerssuch as calcium carbonate or talc, processing aids, curatives, blowingagents, and many other materials to meet performance requirements).These ingredients are typically mixed together in a one or two stepprocess prior to shipping to an extrusion facility. At the extrusionfacility, the ingredients and rubber compound(s) are extruded intoautomotive glass run weatherstrips.

The extrusion process can include many stages depending on the type ofEPDM weatherstrip being manufactured. For example, extrusion lines of upto 80 yards in length that are powered by natural gas and/or electricitymay be required. Much of the natural gas and/or electricity is used tofuel hot air ovens, microwaves, infrared ovens, or other types ofequipment used to vulcanize the EPDM rubber compounds. The vulcanizationprocess also produces fumes that must be vented and monitored to complywith environmental requirements. This process can be very timeconsuming, costly, and environmentally unfriendly.

It would be desirable to develop new compositions and methods formanufacturing weatherstrips which are simpler, lighter in weight, havesuperior long-term load loss (LLS) (i.e., ability to seal the glass andwindow for a long term), and more environmentally friendly.

BRIEF DESCRIPTION

The present disclosure relates to compositions including silane-graftedpolyolefins.

The compositions are useful in the production of weatherstrips, forexample glass run weatherstrips for use in vehicles. The weatherstripsmay be components of glass sealing systems with good surface appearance,good weathering, and good sealing capability against wind, noise, andwater leaks.

Disclosed in embodiments is a weatherstrip comprising a silane-graftedpolyolefin.

Disclosed in other embodiments is a method for manufacturing acomposition that finds use as a weatherstrip. The method includesextruding a composition that contains a silane-grafted polyolefin. Theextruded composition is molded into the shape of the weatherstrip. Themethod may further include grafting silanes to a polyolefin to form thesilane-grafted polyolefin.

Disclosed in further embodiments is a composition comprising asilane-grafted polyolefin.

These and other non-limiting characteristics of the disclosure are moreparticularly disclosed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a brief description of the drawings, which arepresented for the purposes of illustrating the exemplary embodimentsdisclosed herein and not for the purposes of limiting the same.

FIG. 1 is a side perspective view of a portion of an automotive vehicle.

FIG. 2 is a cross-sectional view of a beltline weatherstrip portion.

FIG. 3 is a cross-sectional view of a below belt weatherstrip portion.

FIG. 4 is a graph illustrating the stress/strain behavior of acomposition of the present disclosure compared to two EPDM compounds.

DETAILED DESCRIPTION

A more complete understanding of the components, processes andapparatuses disclosed herein can be obtained by reference to theaccompanying drawings. These figures are merely schematicrepresentations based on convenience and the ease of demonstrating thepresent disclosure, and are, therefore, not intended to indicaterelative size and dimensions of the devices or components thereof and/orto define or limit the scope of the exemplary embodiments.

Although specific terms are used in the following description for thesake of clarity, these terms are intended to refer only to theparticular structure of the embodiments selected for illustration in thedrawings, and are not intended to define or limit the scope of thedisclosure. In the drawings and the following description below, it isto be understood that like numeric designations refer to components oflike function.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise.

Numerical values in the specification and claims of this applicationshould be understood to include numerical values which are the same whenreduced to the same number of significant figures and numerical valueswhich differ from the stated value by less than the experimental errorof conventional measurement technique of the type described in thepresent application to determine the value.

All ranges disclosed herein are inclusive of the recited endpoint andindependently combinable (for example, the range of “from 2 to 10” isinclusive of the endpoints, 2 and 10, and all the intermediate values).The endpoints of the ranges and any values disclosed herein are notlimited to the precise range or value; they are sufficiently impreciseto include values approximating these ranges and/or values.

A value modified by a term or terms, such as “about” and“substantially,” may not be limited to the precise value specified. Theapproximating language may correspond to the precision of an instrumentfor measuring the value. The modifier “about” should also be consideredas disclosing the range defined by the absolute values of the twoendpoints. For example, the expression “from about 2 to about 4” alsodiscloses the range “from 2 to 4.”

FIG. 1 shows a portion of an automotive vehicle 100 including a frontdoor 102. The front door 102 includes a window opening 104 and a window106 that can be selectively raised and lowered relative to the door. Aweatherstrip 110 surrounds selective perimeter portions of the window(e.g., side and upper portions when the window is closed). Thisweatherstrip 110 may be a glass run weatherstrip. The weatherstrip 110may be formed as separate weatherstrip portions that engage differentperimeter portions of the window. In some embodiments, the weatherstripportions are integrally joined together as a module or a singleweatherstrip assembly.

A lower edge of the window opening, as defined by the door, may bereferred to as a beltline 120. Extending along the beltline 120 is abeltline weatherstrip portion or beltline portion of the weatherstripmodule identified as 122.

A cross-sectional view of the beltline weatherstrip 122 is shown in FIG.2. The beltline weatherstrip includes a body 124 formed as an inverted,generally U-shaped component in cross-section having first and secondlegs 126, 128 having inwardly extending gripping portions 130 thatengage a door panel 132. The beltline weatherstrip 122 further includesa seal lip 134 that is flexible relative to the body, and is oftentimesformed of a different material (e.g., a lower durometer rubber orplastic) than the rubber or EPDM polymer composition of the body 124. Alow friction material 136 is typically provided along that portion ofthe seal lip 134 that is configured for sliding engagement with themovable glass on the vehicle door window 106. It is not uncommon for thebeltline weatherstrip 122 to be formed as a co-extruded structure wherethe different regions or portions of the integrated beltlineweatherstrip are formed from different materials in order to servedifferent functions. For example, the body 124 may be a higher durometermaterial while the seal lip 134 requires flexibility and thus ispreferably a lower durometer material that may also incorporate a lowfriction material.

Illustrated in FIG. 3 is a cross-sectional view of another or below beltweatherstrip portion 140 of the glassrun weatherstrip. For example,below belt portions 142, 144 located in an interior cavity of the door102 may have a configuration as generally illustrated in FIG. 3.Specifically, the below belt weatherstrip portion has an outer rigidsupport member 146 shown here as a generally U-shaped component thatreceives or supports the below belt weatherstrip portion 140. Upstandinglegs 148, 150 form a channel with base 152 that receives theweatherstrip portion 140. The weatherstrip portion 140 is unsupported,i.e., it does not have a rigid support member encased within the rubberor EPDM polymer of which the weatherstrip portion is made. First andsecond legs 160, 162 extend generally upwardly and outwardly from a baseportion 164 so that this below belt weatherstrip portion 140 likewisehas a generally U-shaped conformation adapted to receive a perimeteredge of the window 106. Retaining flanges 166, 168 are provided alongouter edges of the base portion 164 while flexible seal lips 170, 172are flexibly joined at outer ends of the respective legs 160, 162.Again, the flexible seal lips 170, 172, and even the retaining flanges166, 168 may be formed of a different material than the remaining rubberof the weatherstrip portion 140. Further, those portions of the body(comprised of legs 160, 162 and base 164) that are adapted to engage thewindow 106 preferably have a hardened surface, while the seal lips 170,172 may have a low friction surface where the seal lips engage thewindow edge.

The weatherstrips are formed from a composition including asilane-grafted polyolefin. The silane-grafted polyolefin may be asilane-grafted polyolefin elastomer. The silane-grafted polyolefin maybe cross-linked upon exposure to moisture and/or heat to form anelastomeric material. The cross-linked polyolefin can be used in placeof existing TPV and EPDM rubber formulations to manufacture, forexample, automotive weatherstrips.

Advantageously, the compositions may require a limited number ofingredients (e.g., 10, 9, 8, 7, 6, 5, 4, or 3 ingredients). Theingredients may be combined at an extruder during extrusion (e.g., asingle-step Monosil process or a two-step Sioplas process), therebyeliminating the need for additional steps of mixing and shipping rubbercompounds prior to extrusion.

FIG. 4 illustrates the superior stress/strain behavior of an exemplarymaterial of the present disclosure relative to two existing EPDMmaterials. In particular, FIG. 4 displays a smaller area between thestress/strain curves for the silane-grafted and cross-linked polyolefin,versus the areas between the stress/strain curves for EPDM compound Aand EPDM compound B. This can be desirable for most automotive glass runweatherstrip applications. Elastomeric materials typically havenon-linear stress-strain curves with a significant loss of energy whenrepeatedly stressed. The compositions of the present disclosure mayexhibit greater elasticity (e.g., have linear curves and exhibit verylow energy loss).

The compositions of the present disclosure also reduce the carbonfootprint of extrusion plants used to make the weatherstrips or otherarticles because large natural gas and/or electrical ovens may not berequired for vulcanization. Instead, more efficient low pressure steamchambers can be utilized to vulcanize the silane-grafted polyolefin withminimal fume evolution. In some embodiments, the compositions of thepresent disclosure are curable at room temperature (e.g., at a humidityof at least 55%). Cure times may be reduced at higher temperaturesand/or higher pressures.

The specific gravity of the silane-grafted and cross-linked polyolefinsof the present disclosure may be lower than the specific gravities ofexisting TPV and EPDM formulations. The reduced specific gravity of thematerials leads to lower weight parts, thereby helping automakers meetincreasing demands for improved fuel economy. For example, the specificgravity of a representative material of the present disclosure may befrom about 0.86 g/cm³ to about 0.96 g/cm³ as compared to presently usedmaterials such as TPV which may have a specific gravity of from 0.95 to1.2 g/cm³ and EPDM which may gave a specific gravity of from 1.0 to 1.35g/cm³.

The polyolefin elastomer may be a block copolymer, an ethylene/α-olefincopolymer, a propylene/α-olefin copolymer, EPDM, or a mixture of two ormore of any of these materials. Exemplary block copolymers include thosesold under the trade names INFUSE™ (the Dow Chemical Company) andSEPTON™ V-SERIES (Kuraray Co., LTD.). Exemplary ethylene/α-olefincopolymers include those sold under the trade names VISTAMAXX™ (e.g.,VISTAMAXX 6102) (Exxon Mobil Chemical Company), TAFMER™ (e.g., TAFMERDF710) (Mitsui Chemicals, Inc.), and ENGAGE™ (e.g., ENGAGE 8150) (theDow Chemical Company). Exemplary propylene/α-olefin copolymers TAFMER™XM grades (Exxon Mobil Chemical Company). The EPDM may have a dienecontent of from about 0.5 to about 10 weight percent

In some embodiments, the polyolefin is selected from the groupconsisting of: homopolymers of an olefin or a blend of homopolymers,copolymers of two or more olefins or a blend of copolymers, and a blendof homopolymers with copolymers

The olefin may be selected from ethylene, propylene, 1-butene,1-propene, 1-hexene, and 1-octene. The polyolefin may be produced by anyprocess (e.g., using gas phase and solution based using metallocenecatalysis and Ziegler-Natta catalysis) and optionally using any catalystsuitable for polymerizing ethylene and α-olefins. A metallocene catalystmay be used to produce low density ethylene/α-olefin polymers.

Suitable polyethylenes include but are not limited to polyethyleneobtained by homopolymerization of ethylene or copolymerization ofethylene and a higher 1-olefin comonomer.

Suitable polypropylenes include but are not limited to polypropyleneobtained by homopolymerization of propylene or copolymerization ofpropylene and an olefin comonomer.

The term “comonomer” refers to olefin comonomers which are suitable forbeing polymerized with olefin monomers, such as ethylene or propylenemonomers. Comonomers may comprise but are not limited to aliphaticC₂-C₂₀ α-olefins. Examples of suitable aliphatic C₂-C₂₀ α-olefinsinclude ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene,1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene,1-octadecene and 1-eicosene. In an embodiment, the comonomer is vinylacetate. The term “copolymer” refers to a polymer, which is made bylinking more than one type of monomer in the same polymer chain. Theterm “homopolymer” refers to a polymer which is made by linking olefinmonomers, in the absence of comonomers. The amount of comonomer can, insome embodiments, be from greater than 0 to about 12 weight percentbased on the weight of the polyolefin, including from greater than 0 toabout 9 weight percent and from greater than 0 to about 7 weightpercent. In some embodiments, the comonomer content is greater thanabout 2 mole percent of the final polymer, including greater than about3 mole percent and greater than about 6 mole percent. The comonomercontent may be less than or equal to about 30 mole percent. A copolymercan be a random or block (heterophasic) copolymer. In some embodiments,the polyolefin is a random copolymer of propylene and ethylene.

The polyethylene for use in the present disclosure can be classifiedinto several types including, but not limited to, LDPE (Low DensityPolyethylene), LLDPE (Linear Low Density Polyethylene), and HDPE (HighDensity Polyethylene). In another classification, the polyethylene canbe classified as Ultra High Molecular Weight (UHMW), High MolecularWeight (HMW), Medium Molecular Weight (MMW) and Low Molecular Weight(LMW). The polyethylene may be an ultra low density ethylene elastomer.The ultra low density ethylene elastomer may have a density of 0.85g/cm³ or greater, including from about 0.88 to about 0.92 g/cm³.

The polyolefin may include a LDPE/silane copolymer or blend.

The polyolefin, such as polyethylene, can be produced using any catalystknown in the art including, but not limited to, chromium catalysts,Ziegler-Natta catalysts, metallocene catalysts or post-metallocenecatalysts.

In some embodiments, the polyolefin has a molecular weight distributionM_(w)/M_(n) of less than or equal to about 5, including less than orequal to about 4, from about 1 to about 3.5, and from about 1 to about3.

The polyolefin may have a melt viscosity in the range of from about2,000 cP to about 50,000 cP as measured using a Brookfield viscometer ata temperature of about 177° C. In some embodiments, the melt viscosityis from about 4,000 cP to about 40,000 cP, including from about 5,000 cPto about 30,000 cP and from about 6,000 cP to about 18,000 cP.

The polyolefin may have a melt index (T2), measured at 190° C. under a2.16 kg load, of from about 20.0 g/10 min to about 3,500 g/10 min,including from about 250 g/10 min to about 1,900 g/10 min and from about300 g/10 min to about 1,500 g/10 min. In some embodiments, thepolyolefin has a fractional melt index of from 0.5 g/10 min to about3,500 g/10 min.

The polyolefin may be polymerized in two reactors, wherein a firstpolymer is polymerized in the first reactor and a second polymer ispolymerized in the second reactor. The second polymer may be of a highermolecular weight, a different density, and/or be heterogeneous. Thereactors may be connected in series or in parallel.

In some embodiments, a blend of two or more polyolefins is silanatedand/or cured. The blend may include an ethylene/α-olefin polymer and apropylene/α-olefin polymer.

The polymers and resins of the present disclosure may be treated withone or more stabilizers (e.g., antioxidants). The polymers may betreated before grafting, after grafting, before crosslinking, and/orafter crosslinking. Other additives may also be included. Non-limitingexamples of additives include antistatic agents, dyes, pigments, UVlight absorbers, nucleating agents, fillers, slip agents, plasticizers,fire retardants, lubricants, processing aides, smoke inhibitors,anti-blocking agents, and viscosity control agents. The antioxidant(s)may be present in an amount of less than 0.5 weight percent, includingless than 0.2 weight percent of the composition.

In some embodiments, the density of the polyolefin elastomer is lessthan 1.0 g/cm³, including less than about 0.92 g/cm³. The density may befrom about 0.85 g/cm³ to about 0.96 g/cm³. In some embodiments, thedensity is at least 0.84 g/cm³, including at least about 0.862 g/cm³.

The polyolefin elastomer may be present in an amount of from greaterthan 0 to about 100 weight percent of the composition. In someembodiments, the amount of polyolefin elastomer is from about 30 toabout 70 weight percent.

The percent crystallinity of the polyolefin elastomer may be less thanabout 40%, less than about 35%, less than about 30%, less than about25%, or less than about 20%. The percent crystallinity may be at leastabout 10%. In some embodiments, the crystallinity is in the range offrom about 2% to about 60%.

The silane grafted to the polyolefin may be selected from alkoxysilanes,silazanes and siloxanes.

Non-limiting examples of silazanes include hexamethyldisilazane (HMDS orBis(trimethylsilyl)amine). Non-limiting examples of siloxane compoundsinclude polydimethylsiloxane (PDMS) and octamethylcyclotetrasiloxane.

In some embodiments, the silane is an alkoxysilane. As used herein, theterm “alkoxysilane” refers to a compound that comprises a silicon atom,at least one alkoxy group and at least one other organic group, whereinthe silicon atom is bonded with the organic group by a covalent bond.Preferably, the alkoxysilane is selected from alkylsilanes; acryl-basedsilanes; vinyl-based silanes; aromatic silanes; epoxy-based silanes;amino-based silanes and amines that possess —NH₂, —NHCH₃ or —N(CH₃)₂;ureide-based silanes; mercapto-based silanes; and alkoxysilanes whichhave a hydroxyl group (i.e., —OH). An acryl-based silane may be selectedfrom the group comprising beta-acryloxyethyl trimethoxysilane;beta-acryloxy propyl trimethoxysilane; gamma-acryloxyethyltrimethoxysilane; gamma-acryloxypropyl trimethoxysilane;beta-acryloxyethyl triethoxysilane; beta-acryloxypropyl triethoxysilane;gamma-acryloxyethyl triethoxysilane; gamma-acryloxypropyltriethoxysilane; beta-methacryloxyethyl trimethoxysilane;beta-methacryloxypropyl trimethoxysilane; gamma-methacryloxyethyltrimethoxysilane; gamma-methacryloxypropyl trimethoxysilane;beta-methacryloxyethyl triethoxysilane; beta-methacryloxypropyltriethoxysilane; gamma-methacryloxyethyl triethoxysilane;gamma-methacryloxypropyl triethoxysilane; 3-methacryloxypropylmethyldiethoxysilane. A vinyl-based silane may be selected from the groupcomprising vinyl trimethoxysilane; vinyl triethoxysilane; p-styryltrimethoxysilane, methylvinyldimethoxysilane,vinyldimethylmethoxysilane, divinyldimethoxysilane,vinyltris(2-methoxyethoxy)silane, andvinylbenzylethylenediaminopropyltrimethoxysilane. An aromatic silane maybe selected from phenyltrimethoxysilane and phenyltriethoxysilane. Anepoxy-based silane may be selected from the group comprising3-glycydoxypropyl trimethoxysilane; 3-glycydoxypropylmethyldiethoxysilane; 3-glycydoxypropyl triethoxysilane;2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, andglycidyloxypropylmethyldimethoxysilane. An amino-based silane may beselected from the group comprising 3-aminopropyl triethoxysilane;3-aminopropyl trimethoxysilane; 3-aminopropyldimethyl ethoxysilane;3-aminopropylmethyldiethoxysilane; 4-aminobutyltriethoxysilane;3-aminopropyldiisopropyl ethoxysilane;1-amino-2-(dimethylethoxysilyl)propane,(aminoethylamino)-3-isobutyldimethyl methoxysilane;N-(2-aminoethyl)-3-aminoisobutylmethyl dimethoxysilane;(aminoethylaminomethyl)phenetyl trimethoxysilane;N-(2-aminoethyl)-3-aminopropylmethyl dimethoxysilane;N-(2-aminoethyl)-3-aminopropyl trimethoxysilane;N-(2-aminoethyl)-3-aminopropyl triethoxysilane;N-(6-aminohexyl)aminomethyl trimethoxysilane;N-(6-aminohexyl)aminomethyl trimethoxysilane;N-(6-aminohexyl)aminopropyl trimethoxysilane;N-(2-aminoethyl)-1,1-aminoundecyl trimethoxysilane; 1,1-aminoundecyltriethoxysilane; 3-(m-aminophenoxy)propyl trimethoxysilane;m-aminophenyl trimethoxysilane; p-aminophenyl trimethoxysilane;(3-trimethoxysilylpropyl)diethylenetriamine; N-methylaminopropylmethyldimethoxysilane; N-methylaminopropyl trimethoxysilane;dimethylaminomethyl ethoxysilane;(N,N-dimethylaminopropyl)trimethoxysilane;(N-acetylglycysil)-3-aminopropyl trimethoxysilane,N-phenyl-3-aminopropyltrimethoxysilane,N-phenyl-3-aminopropyltriethoxysilane,phenylaminopropyltrimethoxysilane,aminoethylaminopropyltrimethoxysilane, andaminoethylaminopropylmethyldimethoxysilane. An ureide-based silane maybe 3-ureidepropyl triethoxysilane. A mercapto-based silane may beselected from the group comprising 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyl trimethoxysilane, and 3-mercaptopropyltriethoxysilane. An alkoxysilane having a hydroxyl group may be selectedfrom the group comprising hydroxymethyl triethoxysilane;N-(hydroxyethyl)-N-methylaminopropyl trimethoxysilane;bis(2-hydroxyethyl)-3-aminopropyl triethoxysilane;N-(3-triethoxysilylpropyl)-4-hydroxy butylamide;1,1-(triethoxysilyl)undecanol; triethoxysilyl undecanol; ethylene glycolacetal; and N-(3-ethoxysilylpropyl)gluconamide.

The alkylsilane may be expressed with a general formula:R_(n)Si(OR′)_(4-n) wherein: n is 1, 2 or 3; R is a C₁₋₂₀ alkyl; and R′is an C₁₋₂₀ alkyl.

The term “alkyl” by itself or as part of another substituent, refers toa straight or branched or cyclic saturated hydrocarbon group joined bysingle carbon-carbon bonds having 1 to 20 carbon atoms, for example 1 to10 carbon atoms, for example 1 to 8 carbon atoms, preferably 1 to 6carbon atoms. When a subscript is used herein following a carbon atom,the subscript refers to the number of carbon atoms that the named groupmay contain. Thus, for example, C₁₋₆ alkyl means an alkyl of one to sixcarbon atoms. Examples of alkyl groups are methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, f-butyl, 2-methylbutyl, pentyl,iso-amyl and its isomers, hexyl and its isomers, heptyl and its isomers,octyl and its isomer, decyl and its isomer, dodecyl and its isomers.

The term “C₂₋₂₀ alkenyl” by itself or as part of another substituent,refers to an unsaturated hydrocarbyl group, which may be linear, orbranched, comprising one or more carbon-carbon double bonds having 2 to20 carbon atoms. Examples of C₂₋₆ alkenyl groups are ethenyl,2-propenyl, 2-butenyl, 3-butenyl, 2-pentenyl and its isomers, 2-hexenyland its isomers, 2,4-pentadienyl and the like.

An alkylsilane may be selected from the group comprisingmethyltrimethoxysilane; methyltriethoxysilane; ethyltrimethoxysilane;ethyltriethoxysilane; propyltrimethoxysilane; propyltriethoxysilane;hexyltrimethoxysilane; hexyltriethoxysilane; octyltrimethoxysilane;octyltriethoxysilane; decyltrimethoxysilane; decyltriethoxysilane;dodecyltrimethoxysilane: dodecyltriethoxysilane;tridecyltrimethoxysilane; dodecyltriethoxysilane;hexadecyltrimethoxysilane; hexadecyltriethoxysilane;octadecyltrimethoxysilane; octadecyltriethoxysilane,trimethylmethoxysilane, methylhydrodimethoxysilane,dimethyldimethoxysilane, diisopropyldimethoxysilane,diisobutyldimethoxysilane, isobutyltrimethoxysilane,n-butyltrimethoxysilane, n-butylmethyldimethoxysilane,phenyltrimethoxysilane, phenyltrimethoxysilane,phenylmethyldimethoxysilane, triphenylsilanol, n-hexyltrimethoxysilane,n-octyltrimethoxysilane, isooctyltrimethoxysilane,decyltrimethoxysilane, hexadecyltrimethoxysilane,cyclohexylmethyldimethoxysilane, cyclohexylethyldimethoxysilane,dicyclopentyldimethoxysilane, tert-butylethyldimethoxysilane,tert-butylpropyldimethoxysilane, dicyclohexyldimethoxysilane.

The silane compound may be selected from triethoxyoctylsilane,trimethoxyoctylsilane, and a combination thereof.

Examples of silanes include, but are not limited to, those of thegeneral formula CH₂═CR—(COO)_(x)(C_(n)H_(2n))_(y)SiR′₃, wherein R is ahydrogen atom or methyl group; x is 0 or 1; y is 0 or 1; n is an integerfrom 1 to 12; each R′ can be an organic group and may be independentlyselected from an alkoxy group having from 1 to 12 carbon atoms (e.g.,methoxy, ethoxy, butoxy), aryloxy group (e.g., phenoxy), araloxy group(e.g., benzyloxy), aliphatic acyloxy group having from 1 to 12 carbonatoms (e.g., formyloxy, acetyloxy, propanoyloxy), amino or substitutedamino groups (e.g., alkylamino, arylamino), or a lower alkyl grouphaving 1 to 6 carbon atoms. x and y may both equal 1. In someembodiments, no more than one of the three R′ groups is an alkyl. Inother embodiments, not more than two of the three R′ groups is an alkyl.

Any silane or mixture of silanes that can effectively graft to andcrosslink an olefin polymer can be used in the practice of the presentdisclosure. Suitable silanes include, but are not limited to,unsaturated silanes which include an ethylenically unsaturatedhydrocarbyl group (e.g., a vinyl, allyl, isopropenyl, butenyl,cyclohexenyl or a gamma-(meth)acryloxy allyl group) and a hydrolyzablegroup (e.g., a hydrocarbyloxy, hydrocarbonyloxy, or hydrocarbylaminogroup). Non-limiting examples of hydrolyzable groups include, but arenot limited to, methoxy, ethoxy, formyloxy, acetoxy, proprionyloxy, andalkyl, or arylamino groups. In some embodiments, the silanes areunsaturated alkoxy silanes which can be grafted onto the polymer. Otherexemplary silanes include vinyltrimethoxysilane, vinyltriethoxysilane,3-(trimethoxysilyl)propyl methacrylate gamma-(meth)acryloxypropyltrimethoxysilane), and mixtures thereof.

The silane may be present in the silane-grafted polyolefin in an amountof from greater than 0 to about 10 weight percent, including from about0.5 to about 5 weight percent. The amount of silane may be varied basedon the nature of the olefin polymer, the silane, the processingconditions, the grafting efficiency, the application, and other factors.The amount of silane may be at least 2 weight percent, including atleast 4 weight percent or at least 5 weight percent, based on the weightof the reactive composition. In other embodiments, the amount of silanemay be at least 10 weight percent, based on the weight of the reactivecomposition. In some embodiments, the silane content is at least 1%based on the weight of the reactive composition.

Optionally, the crosslinking is initiated by a catalyst or electron beamradiation. Non limiting examples of catalysts include organic bases,carboxylic acids, and organometallic compounds (e.g., organic titanatesand complexes or carboxylates of lead, cobalt, iron, nickel, zinc, andtin). The catalyst may be selected from fatty acids and metal complexcompounds such as metal carboxylates; aluminum triacetyl acetonate, irontriacetyl acetonate, manganese tetraacetyl acetonate, nickel tetraacetylacetonate, chromium hexaacetyl acetonate, titanium tetraacetyl acetonateand cobalt tetraacetyl acetonate; metal alkoxides such as aluminumethoxide, aluminum propoxide, aluminum butoxide, titanium ethoxide,titanium propoxide and titanium butoxide; metal salt compounds such assodium acetate, tin octylate, lead octylate, cobalt octylate, zincoctylate, calcium octylate, lead naphthenate, cobalt naphthenate,dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin maleate anddibutyltin di(2-ethylhexanoate); acidic compounds such as formic acid,acetic acid, propionic acid, p-toluenesulfonic acid, trichloroaceticacid, phosphoric acid, monoalkylphosphoric acid, dialkylphosphoric acid,phosphate ester of p-hydroxyethyl (meth)acrylate, monoalkylphosphorousacid and dialkylphosphorous acid; acids such as p-toluenesulfonic acid,phthalic anhydride, benzoic acid, benzenesulfonic acid,dodecylbenzenesulfonic acid, formic acid, acetic acid, itaconic acid,oxalic acid and maleic acid, ammonium salts, lower amine salts orpolyvalent metal salts of these acids, sodium hydroxide, lithiumchloride; organometal compounds such as diethyl zinc andtetra(n-butoxy)titanium; and amines such as dicyclohexylamine,triethylamine, N,N-dimethylbenzylamine,N,N,N,N′-tetramethyl-1,3-butanediamine, diethanolamine, triethanolamineand cyclohexylethylamine. In some embodiments, the catalyst is selectedfrom ibutyltindilaurate, dioctyltinmaleate, dibutyltindiacetate,dibutyltindioctoate, stannous acetate, stannous octoate, leadnaphthenate, zinc caprylate, and cobalt naphthenate. A single catalystor a mixture of catalysts may be utilized. The catalyst(s) may bepresent in an amount of from about 0.01 weight percent to about 1.0weight percent, including from about 0.25 to about 8 weight percent,based on the total weight of the composition.

In some embodiments, the crosslinking system uses a combination ofradiation, heat, moisture, and crosslinking agent(s). The crosslinkingagent(s) may be present in an amount of from 0.25 to 8 weight percent.

Optionally, a grafting initiator is utilized in the grafting process.The grafting initiator may be selected from halogen molecules, azocompounds (e.g., azobisisobutyl), carboxylic peroxyacids, peroxyesters,peroxyketals, and peroxides (e.g., alkyl hydroperoxides, dialkylperoxides, and diacyl peroxides). In some embodiments, the graftinginitiator is an organic peroxide selected from di-t-butyl peroxide,t-butyl cumyl peroxide, dicumyl peroxide,2,5-dimethyl-2,5-di(t-butyl-peroxy)hexyne-3,1,3-bis(t-butyl-peroxy-isopropyl)benzene,n-butyl-4,4-bis(t-butyl-peroxy)valerate, benzoyl peroxide,t-butylperoxybenzoate, t-butylperoxy isopropyl carbonate, andt-butylperbenzoate, as well as bis(2-methylbenzoyl)peroxide,bis(4-methylbenzoyl)peroxide, t-butyl peroctoate, cumene hydroperoxide,methyl ethyl ketone peroxide, lauryl peroxide, tert-butyl peracetate,di-t-amyl peroxide, t-amyl peroxybenzoate,1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane,α,α′-bis(t-butylperoxy)-1,3-diisopropylbenzene,α,α′-bis(t-butylpexoxy)-1,4-diisopropylbenzene,2,5-bis(t-butylperoxy)-2,5-dimethylhexane, and2,5-bis(t-butylperoxy)-2,5-dimethyl-3-hexyne and 2,4-dichlorobenzoylperoxide. Exemplary peroxides include those sold under the tradenameLUPEROX™ (available from Arkema, Inc.).

In some embodiments, the grafting initiator is present in an amount offrom greater than 0 to about 2 weight percent of the composition,including from about 0.15 to about 1.2 weight percent of thecomposition. The amount of initiator and silane employed may affect thefinal structure of the silane grafted polymer (e.g., the degree ofgrafting in the grafted polymer and the degree of crosslinking in thecured polymer). In some embodiments, the reactive composition containsat least 100 ppm of initiator or at least 300 ppm of initiator. Theinitiator may be present in an amount from 300 ppm to 1500 ppm or 2000ppm. The silane:initiator weight ratio may be from about 20:1 to 400:1,including from about 30:1 to about 400:1 and from about 48:1 to about350:1 and from about 55:1 to about 333:1.

The grafting reaction can be performed under conditions that optimizegrafts onto the interpolymer backbone while minimizing side reactions(e.g., the homopolymerization of the grafting agent). The graftingreaction may be performed in the melt, in solution, in the solid-state,and/or in a swollen-state. The silanation may be performed in awide-variety of equipment (e.g., twin screw extruders, single screwextruders, Brabenders, internal mixers such as Banbury mixers, and batchreactors). In some embodiments, the polyolefin, silane, and initiatorare mixed in the first stage of an extruder. The melt temperature (i.e.,the temperature at which the polymer starts melting and starts to flow)may be from about 120° C. to about 260° C., including from about 130° C.to about 250° C.

The composition optionally includes one or more fillers. The filler(s)may be extruded with the silane-grafted polyolefin. The filler(s) may beselected from metal oxides, metal hydroxides, metal carbonates, metalsulfates, metal silicates, clays, talcs, carbon black, and silicas.These materials may be fumed or calcined.

The metal of the metal oxide, metal hydroxide, metal carbonate, metalsulfate, or metal silicate may be selected from alkali metals (e.g.,lithium, sodium, potassium, rubidium, caesium, and francium); alkalineearth metals (e.g., beryllium, magnesium, calcium, strontium, barium,and radium); transition metals (e.g., zinc, molybdenum, cadmium,scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel,copper, yttrium, zirconium, niobium, technetium, ruthernium, rhodium,palladium, silver, hafnium, taltalum, tungsten, rhenium, osmium, indium,platinum, gold, mercury, rutherfordium, dubnium, seaborgium, bohrium,hassium, and copernicium); post-transition metals (e.g., aluminum,gallium, indium, tin, thallium, lead, bismuth, and polonium);lanthanides (e.g., lanthanum, Cerium, praseodymium, neodymium,promethium, samarium, europium, gadolinium, terbium, dysprosium,holmium, erbium, thulium, ytterbium, and lutetium); actinides (e.g.,actinium, thorium, protactinium, uranium, neptunium, plutonium,americium, curium, berkelium, californium, einsteinium, fermium,mendelevium, nobelium, and lawrencium); germanium; arsenic; antimony;and astatine.

The filler(s) may be present in an amount of from greater than 0 toabout 50 weight percent, including from about 1 to about 20 weightpercent and from about 3 to about 10 weight percent.

One stage silane crosslinking can involve the extrusion of a directmixture of the polymer resin with a silane concentrate that includes acatalyst. The extrudate can be subsequently crosslinked in the presenceof moisture/heat. In two-stage crosslinking, silane is first grafted tothe polymer molecular chains according to known reactions to yield asilane grafted copolymer.

Subsequently, the silane-grafted copolymer is mixed with a silanolforming condensation catalyst and then exposed to humidity and/or heatto effect crosslinking of the copolymer in a two-step reaction.Alternatively, the composition can be crosslinked via ‘Ambicat’ wherethe ambient moisture is sufficient to crosslink over a longer timeperiod (e.g., about 48 hours). First, the water hydrolyzes the silane toproduce a silanol. The silanol then condenses to form intermolecular,irreversible Si—O—Si crosslink sites.

The amount of crosslinked silane groups, and thus the final polymerproperties, can be regulated by controlling the production process,including the amount of catalyst used. A gel test (ASTM D2765) can beused to determine the amount of crosslinking.

Curing may occur over a time period of from greater than 0 to about 20hours. In some embodiments, curing takes place over a time period offrom about 1 to about 8 hours, including from about 3 to about 6 hours.

The temperature during curing may be from about 50 to about 150° C.,including from about 80 to about 100° C. and from about 85 to about 95°C.

The humidity during curing may be from about 30 to about 100% includingfrom about 40 to about 100% and from about 50 to about 100%.

The number average molecular weight of the grafted polymers may be inthe range of from about 4,000 g/mol to about 30,000 g/mol, includingfrom about 5,000 g/mol to about 25,000 g/mol and from about 6,000 g/molto about 14,000 g/mol. The weight average molecular weight of thegrafted polymers may be from about 8,000 g/mol to about 60,000 g/mol,including from about 10,000 g/mol to about 30,000 g/mol.

Optionally, the compositions and/or articles formed therefrom furtherinclude one or more TPVs and/or EPDM with or without silane graftmoieties. In some embodiments, the compositions and/or articles furtherinclude other homopolymers, copolymers, and/or terpolymers of ethylene(e.g., LDPE, grafted polymers, maleated polymers, EVA copolymers,ethylene n-butyl acrylate copolymers, and ethylene methacrylatecopolymers); homopolymers, copolymers, and/or terpolymers of propylene;rubbery block copolymers (e.g., copolymers having A-B-A configurations,A-B-A-B-A-B configurations, A-B configurations, and radial blockcopolymers); and other olefin-based polymers. In some embodiments, theadditional polymers are present in an amount of up to 20 weight percentof the composition.

The compositions and/or articles may also include waxes (e.g., paraffinwaxes, microcrystalline waxes, HDPE waxes, LDPE waxes, thermallydegraded waxes, byproduct polyethylene waxes, optionally oxidizedFischer-Tropsch waxes, and functionalized waxes).

Tackifying resins (e.g., aliphatic hydrocarbons, aromatic hydrocarbons,modified hydrocarbons, terpens, modified terpenes, hydrogenatedterpenes, rosins, rosin derivatives, hydrogenated rosins, and mixturesthereof) may also be included. The tackifying resins may have a ring andball softening point in the range of from 70° C. to about 150° C. and aviscosity of less than about 3,000 cP at 177° C.

The compositions may include one or more oils. Non-limiting types ofoils include white mineral oils and naphthenic oils.

The compositions may be extruded into pellets, pillows, or any otherconfiguration prior to the formation of the final article.

Non-limiting examples of articles the compositions may be used tomanufacture include weather seals such as static seals (e.g., glass runchannels) including molded details/corners, dynamic seals (e.g., primaryand secondary body and door seals, other body closure seals, includinghood-to-cowl, lift gate, etc.), sunroof seals, convertible top seals,mirror seals, body-panel interface seals, stationary window moldings,glass encapsulations, cut-line seals, greenhouse moldings, occupationdetector system sensor switches, rocker seals, outer and inner belts,auxiliary and margin seals, edge protector/gimp seals, and below-beltbrackets and channels; automotive hoses such as coolant hoses, airconditioning hoses, and vacuum hoses; anti-vibration system (AVS)components such as mounts (e.g., engine, body, accessory, component),dampers, bushings, strut mounts, and isolators; coatings such ascoatings for brake lines, fuel lines, transmission oil cooler lines,brackets, cross members, frame components, body panels and components,suspension components, wheels, hubs, springs, and fasteners; airdeflectors, spoilers, fascia, and trim; building, window, and doorseals; boots, bellows, and grommets; gaskets (e.g., pneumatic and/orhydraulic gaskets); wire and cable sheathing; tires; windshield wipersand squeegees; floor mats; pedal covers; automotive belts; conveyorbelts; shoe components; marine bumpers; O-rings; valves and seals; andsprings (e.g., as substitutes for mechanical metal springs).

This written description uses examples to describe the disclosure,including the best mode, and also to enable any person skilled in theart to make and use the disclosure. The patentable scope of thedisclosure is defined by the claims, and may include other examples thatoccur to those skilled in the art. Such other examples are intended tobe within the scope of the claims if they have structural elements,components, or materials that do not differ from the literal language ofthe claims, or if they include equivalent structural elements,components, or materials with insubstantial differences from the literallanguage of the claims. The above examples are merely illustrative ofvarious aspects of the present disclosure, wherein equivalentalterations and/or modifications will occur to others skilled in the artupon reading and understanding this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described components (assemblies, devices, systems, and the like),the terms (including a reference to “means”) used to describe suchcomponents are intended to correspond, unless otherwise indicated, toany component which performs the specified function of the describedcomponent (i.e., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the illustrated implementations of the disclosure. Inaddition, although a particular feature of the disclosure may have beenillustrated and/or described with respect to only one of severalimplementations, such feature may be combined with one or more otherfeatures of the other implementations as may be desired and advantageousfor any given or particular application. Also, to the extent that theterms “including”, includes”, “having”, “has”, “with”, or variantsthereof are used in the detailed description and/or in the claims, suchterms are intended to be inclusive in a manner similar to the term“comprising. Moreover, this disclosure is intended to seek protectionfor a combination of components and/or steps and a combination of claimsas originally presented for examination, as well as seek potentialprotection for other combinations of components and/or steps andcombinations of claims during prosecution.

The invention claimed is:
 1. A weatherstrip consisting essentially of aweatherstrip composition, the weatherstrip composition consisting of: asilane-grafted polyolefin having a density of from about 0.86 g/cm³ toabout 0.96 g/cm³; and optionally one or more additives selected from thegroup consisting of antistatic agents, dyes, pigments, UV lightabsorbers, nucleating agents, fillers, slip agents, plasticizers, fireretardants, lubricants, processing aides, smoke inhibitors,anti-blocking agents, and viscosity control agents; wherein thepolyolefin is selected from the group consisting of a propylene/α-olefincopolymer and a blend of propylene/α-olefin copolymer with anethylene/α-olefin copolymer.
 2. A method for manufacturing aweatherstrip comprising: grafting silanes to a polyolefin to form asilane-grafted polyolefin; extruding a composition comprising thesilane-grafted polyolefin having a density of from about 0.86 g/cm³ toabout 0.96 g/cm³, a condensation catalyst, and optionally one or moreadditives selected from the group consisting of antistatic agents, dyes,pigments, UV light absorbers, nucleating agents, fillers, slip agents,plasticizers, fire retardants, lubricants, processing aides, smokeinhibitors, anti-blocking agents, and viscosity control agents; andmolding the extruded composition into the shape of the weatherstrip;wherein the polyolefin is a propylene/α-olefin copolymer.
 3. The methodof claim 2, wherein the grafting is performed in a melt.
 4. The methodof claim 2, wherein the grafting is performed in solution.
 5. The methodof claim 2, wherein the grafting is performed in a solid-state.
 6. Themethod of claim 2, wherein the grafting is performed in a swollen-state.7. A weatherstrip comprising: a weatherstrip composition that comprises:a silane-grafted polyolefin having a density of from about 0.86 g/cm³ toabout 0.96 g/cm³, wherein the polyolefin is a propylene/α-olefincopolymer.